Got gzk green .66 longevity is crap, just snaps without warning anywhere from the pouch tie to the fork tie,gzk green .72 seems to last a bit longer, starts to rip at or just in front of the pouch ties, got .72 gzk black also prone to sudden snapping anywhere, got .72 gzk orange lasts longer than the green and black not as powerful and a softer draw, also got .70 red precise gen 1 lasts longer than gzk but if temp dips into single figures power drops right off. had lots of hard face slaps with gzk, be warned folks.